Discharge recording

ABSTRACT

A discharge recording blank comprises a paper backing having a conductive surface formed by a base coating of conductive powdered carbon, and an outer powdered coating formed on the conductive surface. The outer powdered coating consists of nonconductive finely divided powder such as resin powder and/or pigment powder which is selected from white, gray or colored organic or inorganic pigment. The outer powdered coating is removed in localized areas in response to applied electric signals so as to expose the paper surface. Images recorded on the blank can also be transferred to another usual paper.

United States Patent 1 Sato et al.

[4 1 Sept. 9, 1975 DISCHARGE RECORDING [73] Assignee: Fuji Photo Film C0., Ltd., Minami- Ashigara, Japan [22] Filed: Nov. 6, 1973 [21] Appl. No.: 413,302

Related U.S. Application Data [63] Continuation-impart of Ser. No. 224,600, Feb. 8,

1972, abandoned.

[30] Foreign Application Priority Data Feb. 9, 1971 Japan 46-5405 [52] U.S. Cl 427/122; 427/58 [51] Int. Cl. B44D 1/18 [58] Field of Search 117/216, 217, 215, 29, 117/25, 16

[56] References Cited UNITED STATES PATENTS 3,263,604 8/1966 Dalton 101/1492 Pribble 117/216 Dalton 117/201 Primary Examiner-Cameron K. Weiffenbach Assistant Examiner-Ralph E. Varndell Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn and Macpeak 5 7 1 ABSTRACT A discharge recording blank comprises a paper backing having a conductive surface formed by a base coating of conductive powdered carbon, and an outer powdered coating formed on the conductive surface. The outer powdered coating consists of nonconductive finely divided powder such as resin powder and/or pigment powder which is selected from white, gray or colored organic or inorganic pigment.

The outer powdered coating is removed in localized areas in response to applied electric signals so as to expose the paper surface.

Images recorded on the blank can also be transferred to another usual paper.

16 Claims, No Drawings DISCHARGE RECORDING CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part ap plication of earlier application Ser. No. 224,600 filed Feb. 8, 1972, now abandoned, which claims priority from Feb. 9, 1971, based on Japanese Application No.

BACKGROUND OF THE INVENTION 1. Field of the Invention V This invention relates to discharge recording suitable for repeated use as a facsimile for image-like reproduction of letters, signs, figures, etc. and characterized by adhering non-conductive fine powder on the coarse surface of the conductive layer having conductive carbon black.

2. Description of the Prior Art In a prior discharge recording blank, a surface of a paper backing is coated, which surface has further coated thereon a molybdenum type pigment in a binder such as a resin to make an outer recording coating (US. Pat. No. 3,265,531 According to this prior art recording method. when an electric signal is applied to the recording blank, the electric discharge arises between the recording stylus and the conductive coating via the pigment/binder coating. A discharge breakdown occurs locally on the surface of the pigmentlbindcr coating to scratch in response to the applied electric signal. Marking is thus accomplished. However, this prior art method has disadvantages in that unusually irritating odors and smoke are generated due to the unavoidable decomposition of the binder employed accompanied by the heat of the discharge breakdown. In addition, the use of a binder automatically requires for a conductive coating a relatively low resistivity of, for example, less than. l Q/cm i.e., a relatively high conductivity. This results in poor recording since electric charges tend to be spread out without correctly corresponding to the electric signals applied. Besides, the prior art discharge recording blank can not be re used since the surface of the recording blank is locally scratched to fix an image thereon after electric signals are once applied to the recording blank. The thus formed image can, of course, not be transferred to another paper. The prior art discharge recording blank has also a disadvantage in that the discharge recording blank has decreased flexibility or softness of paper due to the use of a binder.

Thcrefore,-it is desired to improve the described disadvantages.

SUMMARY OF THE INVENTION It is an object of the invention to provide adischarge recording blank comprising a conductive carbon coating and a bindcrless non-conductive powdered coating which operates efficiently without deterioration of recording fidelity.

It is a further object of thc'invention to provide a discharge recording blank which provides a clear marking having high contrast.

It is a further object of the invention to provide an inexpensive and re-usable discharge blank.

It is another object of the invention to provide an ad= vantageous discharge recording method.

DETAILED DESCRIPTION OF THE INVENTION According to the invention, a paper support is coated with a mixture of conductive powdered carbon and resin as a binder to form a black conductive layer thereon. The conductive layer can also be formed by incorporating powdered carbon during processing of the paper, e.g., upon sizing. Finally, the paper support has a conductive surface. Onto the conductive surface, a non-conductive finely divided powder is poured or dispersed to form-an outer powdered coating. Thenonconductive finely divided powder is merely attached to the conductive surface in a powdery state. It may be considered that the adhesion of the powder to the surface arises from Coulombs forces and Van der Waals forces. The powdered coating looks white due to the scattering of light when the non-conductive finely di-' vided powder is attached to the surface of the black conductive coating. After the non-conductive powder is attached to the surface of the conductive coating, the recording blank is set to the facsimile to accomplish the recording. Then, an electric discharge is caused between the conductive coating and a recording conductive stylus, so that the non-conductive powder is blown away in localized areas to expose the black conductive coating. Accordingly, the stronger the scattering of light becomes due to the powder, the higher the contrast of the recording becomes.

In addition, the smaller the particle size becomes, the easier the adhesion of the-powdcr onto the conductive support becomes. Therefore, powders having a small particle size are preferred for the discharge recording blank of this invention. The adhesive property varies with the kind of powders.

The particle size of the non-conductive powder is not limited so long as, of course, the discharge recording blank of the present invention meets the objects heretofore recited, that is, yields a re-usable discharge blank having high recording fidelity. However, generally speaking, the average particle size of the nonconduetive powder is of from 0.05- .1., preferably 0.l-50u. It is most preferred that the particle size of the powder ranges from 0.5 to 20a, since difficulty would occur upon re-use or transferring to a usual paper due to difficulty in removal, i.e., when the particle size of the powder'is too small, the non-conductive powder is packed in a miniature hollows of the conductive surface if rubbed with the finger.

This invention can employ non-conductive finelydivided powders in a broad range, so long as the objects of the present invention are met. In general, the finely divided powder in accordance with the present invention is selected from inorganic or organic pigment particles, resin particles or mixtures thereof. The pigment which can be employed in accordance with the present invention include white, gray or colored organic or inorganic pigments which are non-conductive. The term colored means colors opposite to white-and-black color and thus, colored pigments" include all colored pigments other than white, grey and black. Since the non-conductive pigment coating must be in a powdery state which results in White appearance by scattering light, deep or strongly colored pigments can effectively be employed in accordance With the present invention so long as they tIre'non-conductive. In general, it is most preferred to employ pigments havinglightness of equal to or greater than about 3 on the Munsell scale in order to field high contrast against the background, though this is not limitativc.

As a white colored powder there are employed an in organic powder such as, basic carbonate, white lead. zinc oxide, lithopone, antimony trioxidc, titanium oxide, zinc sulfite, etc. As a colored powder there are employed an inorganic powder such as, lemon chrome yellow, molybdenum red, red oxide, iron oxide, cadmium pigments mainly composed of cadmium sulfide, ultramarine, iron blue, cobalt blue, eerulean blue, emerald green, mangan violet, vermiliod, biridian (Guignets green); chrome oxide, potassium bichromate, etc; and organic pigment powder such as, Hanza Yellow (Cll680), Benzidine Yellow (C121 100), Valcan Fast Yellow (Cl2l200), Permanent Yellow (Cll2780), Permanent Red (Cll2075), Toluidine Red (Cll2l20), Brilliant Fast Scarlet (C1123 l5), Watchung Red (Cll5865), Lithol Red (Cll5630), Brilliant Carmine 6B(Cll5850), Brilliant Scarlet G (Cll5800, Rhodamine oGlake (Cl45l60), Rhodamine B Lake (Cl45l90). Crystal violet Lake (CI42555), Victoria Blue Lake (Cl44045), Phthalocyanine Blue B (Cl74l60), Fast Sky Blue (Cl74200), Pigment Green B 010006 etc.

Specific examples of resin particle which can be employed as a non-conductive finely divided powder in accordance with the invention include polystyrene, polyethylene. phenol resin, maleic acid resin, polyvinyl chloride resin, polyurethane resin, rosin, etc., which are employed in a powdery state, singly or in combination with the pigment particles described above. There is no limitation to the mixing ratio of the pigment powder and the resin.

The resin employed as a powdered coating has no function as a binder. Even if the resin is employed as a mixture with the pigment described above, the resin in the mixture can not be a binder since the mixture must be in a powdery state since it must be capable of being blown away in response to electric signals applied or so as to easily remove by rubbing with a finger, which is mandatory in the present invention.

As earlier indicated, the non-conductive finely divided powder in accordance with the present invention is merely attached to the surface of the conductive coating, which maintains its form as a powder even after coating onto the surface of the conductive coating. Thus. the powder may be removed if strongly rubbed with the finger. Accordingly, the recorded images are mechanically weak, but by utilizing the property, on the other hand, it is possible that the residual powder is removed to attach the powder to the entire surface of the conductive coating again, and that the recording blank can be set again to the facsimile to accomplish recording. That is, the recording blank can be re-uscd. Besides. it is possible that the residual powder is also transferred to a usual paper. If the color of the powder is appropriately selected, color images can also be obtained by repeating the operation. If the powder is fusible using a heat or a solvent, it may be fixed to the recording blank after recording or transferring to a transferring paper.

In order to attach the non-conductive powder to the surface of the conductive coating, the non-conductive powder may be dispersed or poured to the surface of the conductive coating. In case of using a mixture of pigment particles and resin particles, the pigment particles may merely be mixed with the resin particle. Alternatively, the pigment and resin are kneaded together to form a solid mass and the solid mass is powdered, followed by sieving to obtain the powdered pigment/resin mixture of less than a. The powdered pigment/resin mixture is similarly dispersed or poured onto the conductive surface. From a commercial standpoint, it is convenient to utilize a technique so as to develop electrostatic latent images in an electrophotographic art. For example, in order to employ a a cascade development, glass beads (about 0.50.8 mm) and the nonconductive powders are mixed with each other, where powder is attached to the surface of the glass beads as a carrier by a frictional charging force or the Van der Waals force. Thereafter, the mixture is cascaded to the surface of the conductive coating so that the powder is transferred onto the surface of the conductive coating from the glass bead and the surface is thus uniformly coated with the powder. Alternatively, the powder is absorbed in a cloth or a felt with which the surface of the conductive coating may be rubbed or dusted. Further, the powder may be uniformly attached to the surface of the conductive coating by an eelectrodeposition process. Even further, a suspension of the powder is applied to the surface of the conductive coating, and a phenomenon that the powder is absorbed in the surface of. the conductive coating may be employed after the coated suspension is dried. And still further, a method that chalk is attached by rubbing may be employed. The above method of attaching powder need not be defined and the powder is sufficiently attached by a relatively weak forces such as Coulombs and Van der Waals forces.

The resin employed as a binding material of carbon can widely be selected from resins usually employed as a binder in the art. Alkyd resins, acrylic resins. vinyl acetate resins, etc. are most preferred from commercial aspects.

The conductive layer requires for black colored appearance at the surface thereof so that the contrast against the background, i.e., the outer powdered coating, can be enhanced. Specific examples of carbon include carbon black, graphite, etc. The surface resistance of the conductive surface is not overly important so long as the objects of the present invention are satisfied. However, a resistivity of from about 10 to about 10'' Gem is preferred in order to exactly reproduce an image in response to electric signals applied. This value of the resistivity is relatively high as compared to that of the prior art discharge recording blank. That is, moderate conductivity is suffieicnt in the present invention to obtain clear image. The surface resistance may of course be changed to the resistance of the usual insulator at a state where the powder is attached thereto, but it becomes almost the same value after recording.

A further understanding of the invention will be gained from a consideration of the following examples of referred embodiments of the invention.

EXAMPLE 1 Utilizing cascade development method, a powdered coating was provided.

A uniform mixture composed of glass beads having a particle diameter of().5-().8 mm and titanium dioxide having a particle diameter of 0.2-0.5 p. was poured onto the surface of the conductive coating formed on a black paper having a resistivity of 8 X 10 Q/cm (which has been utilized as a light shielding paper of photographic films such as Ncopan SS film made by the Fuji Photo Film Co., Ltd.) to form a white powdered coating.

The recording blank thus produced was set to the facsimile. Then, a clear recording with a high contrast was obtained by applying A-C 1O KH 200 volts, and mA of electric signal thereto.

EXAMPLE 2 The surface of the conductive coating of the same paper as in Example l was rubbed with chalk to form a white powdered coating. A clear recording was obtained by the same operation as the Example 1.

EXAMPLE 3 Carmine 6B and polyyvinyl chloride instead of the Brilliant Carmine 6B, the surface of the conductive coating was uniformly coated with mixed powders by the same operation as in Example 1. After recording, the images were transferred to a usual paper by corona discharge. and thermal fixation could be carried out.

EXAMPLE 4 When the mixture composed of the glass beads and. the titanium dioxide employed in Example 1 was again cascaded to the recording blank recorded by Example 1. the entire surface of the blank became white. The blank was again set to the facsimile to accomplish the recording similar to Example lv EXAMPLE 5 Instead of the light shielding paper used in Example 1, an art paper having a thickness of 80 ,u was utilized and otherwise this procedure was identical with Example l. The surface of the paper was coated with a mixture composed of carbon black and resin to make the conductive coating thereon. The coating solution was Dotite Paint S-3S (a mixed solution composed of carbon black, resin, and solvent, made by Fujikura Kasei Co., Ltd.). The thickness of the coating was 5 pafter drying and the resistivity thereof was 2.3Xl0 Q/cm The same white powdered coating as in Example 1 was formed on the conductive surface to produce a recording blank.

EXAMPLE 6 Piccolastic D-125 (trademark of polystyrene made by the Esso Standard Co., Ltd.; m.p,, 125C, molecular weight about 3000) was pulverized in a mortar and sieved to yiled particles of less than u. The powder was treated as in Example 1 to form a discharge recording blank.

The blank could repeatedly be used to give a clear image having high contrast.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

What is claimed is:

l. A discharge recording blank comprising a paper support having a black conductive surface, and a binderless powdered coating consisting of a non-conductive finely divided powder formed on said conductive surface wherein said powder is a pigment selected from the group consisting of organic pigment particles, inorganic pigment particles, resin particles or mixtures thereof, whereby said powdered coating is removed in localized areas in response to applied electric signals so as to expose said black conductive surface in high contrast.

2. The discharge recording blank of claim 1 wherein said non-conductive finely divided powder has a particle size of from 0.05 to u.

3. The discharge recording blank of claim 1 wherein said resin particles are selected from the group consisting of polystyrene, polyethylene, phenol resin, maleic acid resin. polyvinyl chloride resin, polyurethane resin, rosin, or mixtures thereof.

4. The discharge recording blank of claim 1 wherein said black conductive surface exhibits a resistivity of from about 10" to about 10" ohms per square centimeter.

5. The discharge recording blank of claim 4 wherein said black conductive surface is formed by coating a mixture of carbon and a resin binder on said paper sup port.

6. The discharge recording blank of claim 5 wherein said carbon is carbon black or graphite.

7. The discharge recording blank of claim 4 wherein said black conductive surface is formed by incorporating carbon into said paper during the preparation of said paper.

8. The discharge recording blank of claim 7 wherein said carbon is carbon black or graphite.

9. The discharge recording blank of claim 1 wherein said pigment particles have lightness of equal to or greater than about 3 on the Munsell scale.

10. The discharge recording blank of claim 9 wherein said non-conductive finely divided powder has a parti cle size of from 0.05 to 100 ,u.

11. The discharge recording blank of claim 9 wherein said resin particles are selected from the group consisting of polystyrene, polyethylene, phenol resin, maleic acid resin, polyvinyl chloride resin, rosin, or mixtures thereof.

12. The discharge recording blank of claim 9 wherein said black conductive surface exhibits a resistivity of from about 10 to about 10 ohms per square centimeter.

13. The discharge recording blank of claim 12 wherein said black conductive surface is formed by coating a mixture of carbon and a resin binder on said paper support.

14. The discharge recording blank of claim 13 wherein said carbon is carbon black or graphite.

15. The discharge recording blank of claim 12 wherein said black conductive surface is formed by incorporating carbon into said paper during the preparation of said paper.

16. The discharge recording blank of claim 15 wherein said carbon is carbon black or graphite. 

1. A DISCHARGE RECORDING BLANK COMPRISING A PAPER SUPPORT HAVING A BLACK CONDUCTIVE SURFACES, AND A BINDERLESS POWERED COATING CONSISTING OF A NON-CONDUCTIVE FINELY DIVIDED POWER FORMED ON SAID CONDUCTIVE SURFACE WHEREIN SAID POWDER IS A PIGMENT SELECTED FROM THE ROUP CONSISTING OF ORGANIC PIGMENT PARTICLES, INORGANIC PIGMENT PARTICLES, RESIN PARTICLES OR MIXTURES THEREOF, WHEREBY SAID POWDERED COATING IS REMOVED IN LOCALIZED AREAS IN RESPONSE TO APPLIED ELECTRIC SIGNALS SO AS TO EXPOSED SAID BLACK CONDUCTIVE SURFACE IN HIGH CONTRAST.
 2. The discharge recording blank of claim 1 wherein said non-conductive finely divided powder has a particle size of from 0.05 to 100 Mu .
 3. The discharge recording blank of claim 1 wherein said resin particles are selected from the group consisting of polystyrene, polyethylene, phenol resin, maleic acid resin, polyvinyl chloride resin, polyurethane resin, rosin, or mixtures thereof.
 4. The discharge recording blank of claim 1 wherein said black conductive surface exhibits a resistivity of from about 104 to about 105 ohms per square centimeter.
 5. The discharge recording blank of claim 4 wherein said black conductive surface is formed by coating a mixture of carbon and a resin binder on said paper support.
 6. The discharge recording blank of claim 5 wherein said carbon is carbon black or graphite.
 7. The discharge recording blank of claim 4 wherein said black conductive surface is formed by incorporating carbon into said paper during the preparation of said paper.
 8. The discharge recording blank of claim 7 wherein said carbon is carbon black or graphite.
 9. The discharge recording blank of claim 1 wherein said pigment particles have lightness of equal to or greater than about 3 on the Munsell scale.
 10. The discharge recording blank of claim 9 wherein said non-conductive finely divided powder has a particle size of from 0.05 to 100 Mu .
 11. The discharge recording blank of claim 9 wherein said resin particles are selected from the group consisting of polystyrene, polyethylene, phenol resin, maleic acid resin, polyvinyl chloride resin, rosin, or mixtures thereof.
 12. The discharge recording blank of claim 9 wherein said black conductive surface exhibits a resistivity of from about 104 to about 105 ohms per square centimeter.
 13. The discharge recording blank of claim 12 wherein said black conductive surface is formed by coating a mixture of carbon and a resin binder on said paper support.
 14. The discharge recording blank of claim 13 wherein said carbon is carbon black or graphite.
 15. The discharge recording blank of claim 12 wherein said black conductive surface is formed by incorporating carbon into said paper during the preparation of said paper.
 16. The discharge recording blank of claim 15 wherein said carbon is carbon black or graphite. 